The present invention relates to a rotary electric machine.
Japanese Laid-Open Patent Publication No. 2008-43099 describes an example of a rotary electric motor in which a permanent magnet is omitted from a rotor and the rotor is magnetized by a field winding instead of a permanent magnet. With the rotary electric motor of Japanese Laid-Open Patent Publication No. 2008-43099, a field winding is arranged at a position close to a winding end (coil end) of a stator winding in an axial direction of a rotary shaft. Further, the field winding is energized to form a magnetic circuit passing through the rotary shaft, a rotor (a salient pole section), a stator, and a field yoke. An N-pole (a magnetic pole) is generated on the salient pole section of the rotor. Thus, with the rotary electric motor of Japanese Laid-Open Patent Publication No. 2008-43099, even in a structure in which a permanent magnet is omitted from the rotor, the rotary electric motor is able to operate in the same manner as a general permanent magnet synchronous motor.
With the rotary electric motor of Japanese Laid-Open Patent Publication No. 2008-43099, when the stator winding is formed by distributed winding, the amount of overhang of a winding end of the stator winding in the axial direction of the rotary shaft increases. In this case, due the overhanging of the winding end of the stator winding, the field winding must be separated from the stator in the axial direction of the rotary shaft. As a result, magnetic resistance of the magnetic circuit (magnetic flux path) may increase due to a longer length of the magnetic circuit.